Isometric view has nothing to do with technological limitations. There were plenty of first-person cRPGs back then (including Bethesda's Daggerfall), and there are isometric ones now (including Diablo 3).
Very true. However, now that Bethesda owns the rights to Fallout, first person is probably all you will see for new Fallout games. Bethesda has only ever done first person games, so I don't look for it to change. I too loved the old isometric games, but am perfectly content with first person Fallout. If they will just fix VATS, bring back traits and low intelligence dialogue options, and improve the quest writing I'll be happy as a clam. Oh, and keep those Fallout games coming!